Fuel delivery issue I think.... 1978 Mercruiser 260 Qjet 4 barrel pics added

[yutopia090987]

Hello everyone this is my first post after reading through almost every post lol. I will try and make this as short as possible. My first boat purchase 1978 Sea ray 240 cc. Bad experience so far. I had to have an engine installed which a marine mechanic/ boat junk yard sold me an engine for 800$ and installed for another 1200$. I ran it on ears in the driveway it ran decent, the only thing was you had to hold the choke closed by hand to get it to start. So a friend of mine put a spring to hold it almost closed. I took it out on the water and the fumes from the exhaust were very bad, my friend said you would get fumes. (which i don't remember as a kid/teen being on boats all the time) I personally think it is running rich. The second time i took it out it seemed like it would not go very fast and then stalled and sputtered all the way through the river, barely making it to the dock. The exhaust sounded different also. I would compare the sound to it missing or popping when it hit on one of the cylinders.

I know the manual choke is not working, but I was wondering if the main intake flap on the carb ( for lack of a better term ) should remain all the way open when running ? Because if I remove the spring he installed that's where it will remain. The engine is a 1978 - 79 Mercruiser 260 alpha one drive and quadrajette 4 bl carb. any help would be greatly appreciated. Thanks:facepalm:

 

[four winns 214]

Re: Fuel delivery issue I think.... 1978 Mercruiser 260 Qjet 4 barrel

Re: Fuel delivery issue I think.... 1978 Mercruiser 260 Qjet 4 barrel

Sounds like to me that the boat needs to go back to the shop.

I'm not an expert in any way, but I do have a Merc engine with a Rochester Quadrajet and have a basic understanding of its operation. Your carb should have a thermostat coil spring mounted on the intake manifold to the left side of the carburetor (left as viewed from the front of the engine). The coil spring is mounted in a two by three inch housing (approximate) and small rod goes from the housing to the choke linkage. That assembly automatically sets the choke to the proper position based on engine temperature. It's a pretty crude mechanism, but it works.

I'm not sure what you mean by "fumes", but you really shouldn't be smelling anything if the engine hatch is closed and the compartment is properly ventilated.

 

[Bondo]

Re: Fuel delivery issue I think.... 1978 Mercruiser 260 Qjet 4 barrel

Re: Fuel delivery issue I think.... 1978 Mercruiser 260 Qjet 4 barrel

Hello everyone this is my first post after reading through almost every post lol. I will try and make this as short as possible. My first boat purchase 1978 Sea ray 240 cc. Bad experience so far. I had to have an engine installed which a marine mechanic/ boat junk yard sold me an engine for 800$ and installed for another 1200$. I ran it on ears in the driveway it ran decent, the only thing was you had to hold the choke closed by hand to get it to start. So a friend of mine put a spring to hold it almost closed. I took it out on the water and the fumes from the exhaust were very bad, my friend said you would get fumes. (which i don't remember as a kid/teen being on boats all the time) I personally think it is running rich. The second time i took it out it seemed like it would not go very fast and then stalled and sputtered all the way through the river, barely making it to the dock. The exhaust sounded different also. I would compare the sound to it missing or popping when it hit on one of the cylinders.

I know the manual choke is not working, but I was wondering if the main intake flap on the carb ( for lack of a better term ) should remain all the way open when running ? Because if I remove the spring he installed that's where it will remain. The engine is a 1978 - 79 Mercruiser 260 alpha one drive and quadrajette 4 bl carb. any help would be greatly appreciated. Thanks:facepalm:

Ayuh,... Sounds like ya bought a used motor, 'n a junk Carb...

Unless they reused yer old carb, I'd take it back to them for a look, see...
If they did reuse yer carb,...
Clean out the fuel system, 'n Rebuild/ Repair, or Replace the Carb...

 

[45Auto]

Re: Fuel delivery issue I think.... 1978 Mercruiser 260 Qjet 4 barrel

Re: Fuel delivery issue I think.... 1978 Mercruiser 260 Qjet 4 barrel

So a friend of mine put a spring to hold it almost closed.

I know the manual choke is not working, but I was wondering if the main intake flap on the carb ( for lack of a better term ) should remain all the way open when running ? Because if I remove the spring he installed that's where it will remain.

Get friends that know more about carbs!

The choke flap on the primary (small) intakes of your Quadrajet should be open ALL the way once the engine has been running for a minute or so. It should be connected to a coil spring in a housing on the opposite side of the carb from the throttle linkage. The coil spring will be heated up and open the choke either from manifold heat (older) or electric (newer). My '87 had manifold heat chokes, yours probably does also.

If you have a spring holding it almost closed, the engine is DEFINITELY running way rich.

 

[yutopia090987]

Re: Fuel delivery issue I think.... 1978 Mercruiser 260 Qjet 4 barrel

Re: Fuel delivery issue I think.... 1978 Mercruiser 260 Qjet 4 barrel

The fumes are coming from the exhaust, along with some black smoke after i run it about two thousand rpm for 30 minutes or so.

 

[yutopia090987]

Re: Fuel delivery issue I think.... 1978 Mercruiser 260 Qjet 4 barrel

Re: Fuel delivery issue I think.... 1978 Mercruiser 260 Qjet 4 barrel

I thought it was supposed to be all the way open. hopefully that is my only problem. i will remove the spring and probably start looking for a new carb. Thanks for the reply

 

[yutopia090987]

Re: Fuel delivery issue I think.... 1978 Mercruiser 260 Qjet 4 barrel

Re: Fuel delivery issue I think.... 1978 Mercruiser 260 Qjet 4 barrel

Get friends that know more about carbs!

The choke flap on the primary (small) intakes of your Quadrajet should be open ALL the way once the engine has been running for a minute or so. It should be connected to a coil spring in a housing on the opposite side of the carb from the throttle linkage. The coil spring will be heated up and open the choke either from manifold heat (older) or electric (newer). My '87 had manifold heat chokes, yours probably does also.

If you have a spring holding it almost closed, the engine is DEFINITELY running way rich.

Well today i installed the assembly to the choke. And also changed out the fouled plugs. She runs like a dream now. I drove out 90 miles to the guys shop and he gave me a brand new coil spring assembly. He said hmmm i cant believe there wasnt one on there. well at least its running good now. Thanks for all your help.